1. Field of the Invention
The present invention relates to an optical viewer at least one plastic lens with improved optical performance.
2. Description of the Prior Art
Various optical viewers are known in the art. Such optical viewers are used in various applications, such as medical and dental clinical applications. Examples of such optical viewers are disclosed in U.S. Pat. Nos. 6,704,142; 6,667,832; 6,201,649; 6,163,413; 5,790,323; 5,667,291; 5,627,690 and 5,515,209, hereby incorporated by reference. The lenses used in such viewers are made from glass due to the better optical characteristics of glass over plastic. Unfortunately, the use of glass lenses in such optical viewers increases the cost and causes such viewers to be relatively heavy. Thus there is a need for a less expensive and lighter weight optical viewer with comparable optical performance.